The color filter for a color liquid crystal display influences the displaying grade of the color liquid crystal display. Above all, it is essential that a black matrix for a color filter not only have sufficient light-shielding ability but also be formed with high resolution for achieving a high opening factor and high contrast.
Chromium-deposited films have so far been used in black matrices for a color filter. However, although black matrices comprising a chromium-deposited film are excellent in light-shielding ability, they have several problems that ghost image is caused as they have a high reflection coefficient leading to the deterioration of visibility, the color filter manufacturing process in which chromium is used in a black matrix is complicated and expensive, and the disposal of chromium waste solutions is problematic.
As has been the circumstances, black matrices comprising a photosensitive resin film having dispersed therein a black pigment and patterned upon a design have been developed. These black matrices have a low reflection coefficient and can be manufactured inexpensively. A radical polymerization type photosensitive resin is used as this photosensitive resin having dispersed therein a black pigment, but a radical polymerization type photosensitive resin is barely hardened in the range where a light reaches, therefore, hardening becomes insufficient in the vicinity of the interface between the film and the substrate. As a result, the development latitude becomes narrow.
Further, in conventional black pigments, even if a photosensitive resin composition is compounded by combining a black pigment with a quinonediazide compound, an alkali-insoluble substance is formed by merely blending, coating and drying the components, as a result, the image contrast is lowered or, in some cases, the composition comes to be substantially insoluble in a developing solution and patterning becomes impossible.